The original High-Mobility Multipurpose Wheeled Vehicles (HMMWV) was the M998. In 1991, the M1097 was developed to fill the need for a vehicle with a higher payload and towed-load rating than was provided by the earlier models. This heavy Humvee has a reinforced frame, heavier springs, tires and rims and other improvements. It is powered by a 190 horsepower turbo supercharged version of the diesel engine, and like the rest of the HMMWV family, the M1097 features full time four-wheel drive and automatic transmission.

Broadened demands placed on the chassis type resulted in a series of increases in the vehicles’ gross vehicle weight rating, along with associated improvements in the drive train. These changes culminated with the expanded capacity variant (ECV), sometimes also known as the Expanded Capacity Humvee (ECH) was developed.

As of 2006, the M1113 became the base vehicle for future HMMWV orders, with the bulk of these consisting of M1151 and M1152 variants.

Beyond the inherent dangers of operating a soft-skinned vehicle in a combat environment, gunners in particular are vulnerable to snipers, IED blasts, and roll-overs due to their exposed position. In response to these problems, the Up-armored Humvee has been developed, which offers protection against most small arms fire, shrapnel and anti-personnel mines.

The latest generation of the HMMWV is based on the M1113 Expanded Capacity Humvee (ECH). These can be distinguished by the box-like forward extension of the grille, as seen on these new M1152 cargo/troop carrier/prime movers photographed at the Fleet Support Division.

The extended air intake visible here is standard on Marine Corps vehicles. However, on army HMMWVs, like this 10th Mountain Division unit photographed March 14, 2006 in Baghdad, the extended air intake is field installed.

By necessity, in Iraq the HMMWV has been fitted with ever-increasing amounts of armor, in an array of configurations. An example of this is the Marine Corps MAK HMMWV (Marine Armor Kit equipped High Mobility Multi-Wheeled Vehicle), an example of which is seen here patrolling downtown Fallujah. USMC

The slant-back M1025 series vehicles are among the most distinctive members of the HMMWV family. While originally separate designations were given to TOW missile carriers and armament carriers, that is no longer the case in US Army practice. US Army Military Police conduct a security patrol near the Iraq-Kuwait Border with this M1025A1 armament carrier in June, 2004. The Soldiers are assigned to the 201st Field Artillery Regiment, tasked with escorting truck convoys into and out of Iraq.

As originally specified, the HMMWV – as typified by the M998 – was an unarmored tactical utility vehicle delivering outstanding off-road performance. A few variants were built with light armor and weapons mounting, but they were the exception rather than the rule. Photo courtesy of AM General

At first glance this looks like a regular production HMMWV, but closer examination reveals that it is in fact a pre-production prototype. The openings surrounding the headlamps are round, as opposed to square openings on production models.

When this prototype was constructed the powerplant had been changed to the GM 6.2-liter diesel. Notice the Jeep-like appearance of the grille, which was not carried over into the production models. Of particular interest are the rounded lower corners of the swing-out windshield panels.

This is the initial AM General HMMWV prototype. As can be seen by comparing this truck to the current vehicle, the basic form of the vehicle did not change much, although details such as the front-end treatment certainly did. Unlike later models, this truck was powered by an air-cooled diesel.

The M1151 is the basis for most HMMWVs being sent into Iraq. Following initial deployments when troops suffered great losses in basic, unarmored vehicles, great effort was put into creating the armored version seen here. Photo courtesy of AM General

Marines with Truck Company, Headquarters Battalion, 2nd Marine Division, hit targets from their HUMVEE during a live fire and maneuver exercise, May 12, designed specifically to combat the insurgency. USMC